Add nil and zls LSP's

nvim/lua/lsp/servers/nil.lua

@@ -0,0 +1,15 @@
+return {
+    cmd = { "nil" },
+    filetypes = { "nix" },
+    root_markers = {
+        "flake.nix",
+        ".git"
+    },
+    settings = {
+        ["nil"] = {
+            formatting = {
+                command = { "nixfmt" },
+            },
+        },
+    },
+}